FEDERAL approval of Education Superintendent Mick Zais’ request to be released from the absurd mandates of the meddlesome No Child Left Behind law is unequivocally good news.

The idea behind NCLB is perfectly legitimate: that students will learn more if we set high expectations and hold our schools and teachers accountable for the results. Like our own Education Accountability Act that predates it by three years, it requires schools to make progress educating not just the middle-class kids who are easy to teach but the disadvantaged ones as well. By grading schools on not just overall test scores but also scores for all demographic subgroups, it makes it impossible for schools with lots of better-off students to mask their failure to teach poor kids.

We’re not convinced that the federal government needs to be involved in public education, but if it is, it needs to provide realistic requirements, and hold all states to the same standard. No Child Left Behind does neither. The law’s long-term requirements are dangerously unrealistic, requiring every student in the country to be “proficient” in reading and math by 2014 — which is possible only if the word “proficient” is stripped of any meaning. And the law gave states so much flexibility in the short-term that they were tempted to game the system by doing precisely that — and many did.

The waiver allows South Carolina to stop squandering its resources on unattainable goals — and stop giving fuel to those opponents who want to incinerate our system of public education — and get back to the work of improving education.

And in fact, Dr. Zais’ critique of Washington’s role in education policy — “If Washington wants to hold states accountable for the results, it should allow states maximum flexibility to affect the outcomes” — could well serve as a template for his efforts to revamp our state’s approach to education. With a twist.

Our state needs to give district and school administrators the authority to design the curriculums that work best — without mandating, say, which reading program they purchase or how many minutes they spend in the classroom each day — and the authority to hire, and fire, personnel as they see fit. And when some of those schools don’t deliver, our state needs to be aggressive about intervening.

The central ideas in Dr. Zais’ plan are sound: eliminating the all-or-nothing approach of NCLB and using student achievement instead of merely longevity and degrees earned to determine teacher pay.

But he and the Legislature need to remember that there’s a world of difference between coming up with a good idea and a writing a law that implements that idea well.

It makes good sense to grade schools on a five-point scale rather than the black-and-white options of perfection and failure. But while it’s ridiculous to label a school a failure because one tiny subgroup of students doesn’t meet expectations, it’s important to preserve the goal behind this taken-to-the-extreme implementation. That means preserving the S.C. rules that stop schools from coasting on the achievements of their best students while ignoring the others.

And while we don’t believe teachers should pick their own evaluation system — just as no group of employees should be able to do that — it is important that we develop a system that most teachers, and especially good teachers, and would-be teachers, consider fair. Despite what you might think if you listen to the most vocal opponents of pay-for-performance, that’s an achievable goal, as long as state officials are willing to work in good faith to achieve it.